This invention relates to a machine tool wherein a tool is moved first at a rapid feed speed to slightly short of a work-to-be-processed, and thereafter is moved at a suitable process feed speed. More particularly, the invention relates to a machine tool provided with a machine frame adapted attachable to a stand, a pneumatic cylinder for reciprocating a quill on the machine frame, and feed control means, for controlling the moving speed of the quill, comprising a hydraulic cylinder which is disposed in parallel to a quill and includes a piston assembly having a projecting portion engageable with the quill and a liquid tank, whereby the machine is under a rapid feed speed until the quill is engaged with the projecting portion and thereafter under a controlled feed speed by the feed control means.
In machine tools of this kind, attaching of the machine frame to the stand has been required now and then to be varied in some ways in respect to the reciprocating direction of the quill according to the shape of the work.
In those machine tools, however, a liquid tank is installed on the machine frame, which tank communicates with a cylinder chamber of the hydraulic cylinder through an opening formed in the tank by way of suitable flow amount regulating means. They are subjected therefore to a problem that the opening formed in the tank must by all means be positioned under the liquid surface of the tank, otherwise air in the tank may be sucked into the hydraulic cylinder chamber by chance, which can paralyze the feed speed control function of the hydraulic cylinder to the quill.
Those conventional machine tools are placed under a strict condition that they should be attached to a stand such that the opening of the tank is positioned beneath the liquid surface, which disadvantageously restricts their use or way of employment.